Our general assessment from the evidence available at this time is that the 2000 census was well executed in many respects. All statutory deadlines for data release were met, and most of the individual operations were completed on or ahead of schedule. Strategies for obtaining public cooperation in completing and mailing back their census forms succeeded in keeping mail response rates at the levels attained in 1990. This outcome represents an important achievement given the large decline in mail response rates from the 1980 census to the 1990 census.
Few instances occurred in 2000 when operations had to be modified in major ways after Census Day. In contrast, the 1990 census experienced serious and unexpected problems in executing such key operations as nonresponse follow-up, and the Census Bureau had to return to Congress to obtain additional funding to complete all needed operations.
One unexpected modification in summer 2000 was the special operation to minimize duplicate housing unit addresses in the Master Address File. This operation deleted 3.6 million people from the census who duplicated another enumeration and reinstated 2.4 million people who were initially believed to be duplicates. It was mounted quickly when the need for it became apparent and completed with little or no apparent adverse effect on other operations.2 Another late change in plans, made early in 2000, was to set aside data capture of long-form information in order to keep short-form processing on schedule.
Most innovations for 2000 appeared effective, but some exhibited problems in implementation that deserve attention. In particular, the MAF development process was problematic in several respects as discussed below. Also, in comparison with 1990, the 2000 census had increased numbers of people who required imputation. Some of the increase was likely due to two design features of 2000: the use of a shorter questionnaire with space to record characteristics for six instead of seven household members, and the use of telephone followup, not supplemented by field work, to contact households whose returns appeared to be incomplete (see Chapter 3). However, some of the increase in people requiring imputation is not readily explained; it may have been due to errors in MAF, problems in follow-up operations, or other factors. More evaluation is needed of the sources and quality of census imputations, as well as of people reinstated in the census due to the special MAF unduplication operation.
On balance, though, the 2000 census appears to have been well carried out, particularly in view of the problems that hampered planning and preparations. The basic design was not finally determined until winter 1998–1999,
Neither the reinstated people described here nor the imputations discussed in the next paragraph are included in the Accuracy and Coverage Evaluation (A.C.E.) Program. The large numbers of such people in 2000 complicate the interpretation of the A.C.E. results when those results are compared with the 1990 Post-Enumeration Survey (see Chapters 7 and 8).